On Fri, 14 Dec 2001, Perrin Harkins wrote: > > I _really_ hate so-called dedicated boxes. They're closed, nasty, > > inflexible and often don't work in _your_ situation. Doing smart > > session-based redirection can be hard with these boxes. > > You can make it work with homegrown solutions, but I've found the dedicated > load-balancing tools (at least Big/IP) to be effective and fairly easy to > work with, even with large loads, failover requirements, and more exotic > stuff like sticky sessions. This is one area where the problem seems to be > well enough defined for most people to use an off-the-shelf solution. > They're often more expensive than they should be, but if you don't have > someone on hand who knows the ipchains or LVS stuff it can save you some > time and trouble.
I couldn't agree more. In terms of managability and scalability, the various software solutions simply add complexity to something that is already so. I've got some experience with Alteon AceDirectors and even though they seem little flakey at times, you do end up with true load balacing. (We have Cisco's solution deployed and they periodically have issues too.) DNS round-robin should be avoided at all costs. It's half-assed at best. In the case of a failure those clients that have that IP cached are SOL. On some of the systems that I've deployed we have a frontend proxy on the same box as the mod_perl with the mod_perl server listening on 127.0.0.1. This is behind an Alteon (or 2). You can put the proxy on a separate box as well but (I've seen some odd problems with TCP connections not working in this situation which I never fully understood but may have had to do with the Alteon being flakey.) Anyway, my advice is to go with a hardware load balancer/intelligent IP switch. In the long term, it will pay for itself in the time recovered from *not* being spent on troubleshooting complex problems. --Jeff -- "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." - Benjamin Franklin, Historical Review of Pennsylvania, 1759.
